Oman (Lepidoptera: Pieridae) - Al Ain Chapter, Emirates Natural ...

common. I observed numerous specimens at all of the
sites mentioned except Jebel Harim, where all but one
of the specimens were found in a single vegetated wadi.
It fed at all sites on the spiny shrub Astragalus
fasciculifolius, but also, at Aqabat Oso, on the more
common pea family member, Tephrosia apollinea, and
in the Jebel Harim area, on the abundant, flowering
Convolvulus acanthocladus.
Although my own sightings of Loew's Blue have all
been at higher elevations, Guichard collected it from the
base of cliffs near Khasab, therefore probably at
elevations no more than about 100m. Guichard's
collections were made in early April, but Larsen failed to
find the species in February 1979 or May 1981. These
observations, coupled with my own, suggest a relatively
consistent brood timing in March and April, consistent
with the observations of Pittaway for central Saudi
Arabia (see Larsen 1983).
Astragalus fasciculifolius is reckoned to be the larval
food plant of Loew's Blue in the Ru'us al-Jibal, and it is
worth noting that this spiny perennial shrub has suffered
more than many other plant species during the recent
drought, because it has been singled out for the special
attention of goats. Beginning in 2000 I began regularly
to encounter specimens from which the animals had
detached the spiny crown of the plant and stripped the
bark from the central stems, exposing the pale yellow-
orange interior (Fig. 3). Presumably this was done for
either dietary or medicinal reasons, to take advantage of
some substance concentrated in or under the bark of
the plant. One result is that in many areas A.
fasciculifolius does not appear to be as common, nor
are its shrubs as large, as they were formerly. This has
apparently not greatly affected the recent fortunes of
Loew's Blue, however, if we can judge from the numbers
in flight in comparison to prior years.
Identification Tips
Like most of the so-called "Blues", the Baton Blue
and Loew's Blue can be determined most reliably in the
field by inspection of the underside. The Baton Blue is
distinguished by having a line of five orange spots on
the underside of the hind wing, parallel to the rear
margin. Many Blues have one or two orange spots at
the interior corner of the hind wing (which are generally
interpreted as false eye spots, intended to decoy
predators away from more vital parts), but only the
Baton Blue has so many.
In addition, when I saw it under calm weather
conditions, the Baton Blue exhibited distinctive flight.
Moving among low vegetation, it tended to hover before
perching, with the body held relatively vertical and the
wings flapping rapidly about an axis perpendicular, not
parallel, to the ground, so that the wing colour did not
show well to an observer standing above. Seeing the
rapid vibration and no obvious colour, I wondered at first
if perhaps I was looking at a ribbonwing.
Loew's Blue is more distinctive by virtue of its
relatively large size and the vivid royal blue colour of the
male upper side. These allow it in many cases to be
determined in flight. As Larsen noted, it can often be
found at or near the spiny shrub Astragalus
fasciculifolius, which is its larval foodplant.
Fig. 3: The spiny shrub Astragalus fasciculifolius, the larval foodplant of Loew's Blue, was
regularly found "de-barked" by goats during the dry years of 1999-2004, presumably for
dietary or medicinal reasons.
References
Gillett, M.P.T. (1995), 'An updated and annotated list
of butterflies recorded from the UAE, the Musandam
Peninsula and the Buraimi - Al Mahdah region of Oman',
Trsbulus 5.2: 16-17.
Larsen, T.B. (1983), 'Insects of Saudi Arabia -
Lepidoptera: Rhopalocera (A Monograph of the
Butterflies of the Arabian Peninsula)', Fauna of Saudi
Arabia 5:333-478.
Larsen, T.B. (1 984) Butterflies of Saudi Arabia and
its Neighbours, Stacey International, London, 160 pp.
Larsen, T.B. and Larsen, K. (1980), Butterflies of
Oman, John Bartholomew and Son, London, 80 pp.
Gary R. Feulner
P.O. Box 31045
Dubai, United Arab Emirates
e-mail: grfeulnerQshuaacapital.com
Tribulus Vol. 15.1 Spring/Summer 2005
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